This is one way of repairing an FICM. I've never been overly impressed with Dorman electronic parts so, for about the same money, I'd send it in to get repaired and upgraded.
You can get an International half shell for like $165 now... I'd go that route before buying the Dorman stuff. Though, IMO, the only real fix is either a BPD unit, or have your current unit repaired. I can't see the Dorman or even the new half shells lasting any longer than the one's on the trucks now.
Take it with a grain of salt, but I would look into having it repair aka reflow the solder
Mine crapped out a couple years ago and with the directions posted online my father reflowed the solder at the points indicated with the directions. Everything looked solid during visual inspection before the repair. We reflowed the solder and it has been rock solid ever since